1. Field of the Invention
The present invention relates to a sheet processing device including a sheet aligning unit that aligns a conveyed sheet recording medium (hereinafter, simply “a sheet”), an image forming apparatus including the sheet processing device, and an image forming system.
2. Description of the Related Art
In a typical sheet processing device including a sheet aligning unit such as a finisher, a processing tray as a sheet aligning unit is configured to be pulled out from the sheet processing device so that a sheet jam occurring in the processing tray can be easily fixed.
Such a mechanism is disclosed in, for example, Japanese Patent Application Laid-open No. H10-129920 and Japanese Patent Application Laid-open No. 2006-273493. A sheet post-processing apparatus disclosed in Japanese Patent Application Laid-open No. H10-129920 has been developed to improve an operating efficiency of a stapler included therein. Specifically, the sheet post-processing apparatus includes a sheet-aligning tray member on which sheets are stacked in a state where the sheets are aligned and a stapling unit having the stapler for binding the sheets stacked on the sheet-aligning tray member. The stapling unit housed between a front side plate and a back side plate of the sheet post-processing apparatus is configured to slide ahead of the front side plate. A slidable distance of the stapling unit is configured to be larger than a distance between the front side plate and the back side plate.
Furthermore, a sheet post-processing apparatus disclosed in Japanese Patent Application Laid-open No. 2006-273493 has been developed to improve operating efficiencies of a process for fixing a sheet jam due to a staple of a stapler and a process for supplying staples to the stapler and to perform these processes safely. Specifically, the sheet post-processing apparatus includes a sheet processing tray and a stapler unit having the stapler for stapling sheets in the sheet processing tray. The sheet processing tray and the stapler unit are separately installed on the sheet post-processing apparatus, and can be separately pulled out from the sheet post-processing apparatus. The stapler is capable of sliding in the same direction as that the stapler unit is pulled out from the apparatus along with the stapler unit. A latch member is provided to the stapler unit so that the stapler unit is prevented from being freely pulled in and out from the apparatus thereby interfering with the apparatus. While the stapler is sliding toward outside the apparatus, the latch member is pressed by having contact with the stapler, and thereby moving toward the apparatus. When the latch member is released from the contact with the stapler, the latch member moves back toward the stapler unit.
Moreover, in a conventional technology, as shown in FIG. 42, a processing tray F has functions of aligning and binding sheets with a jogger and an edge binding stapler. However, any conveying member, such as a roller or a guide plate, is not provided to an inlet portion of the processing tray F, i.e., the processing tray F has no function of conveying the sheets. In addition, in this example, a staple discharge roller as a conveying member is provided to a main body of a finisher.
In this manner, according to conventional technologies, a staple discharge roller is provided to a main body of a sheet processing device, and a processing tray (a sheet aligning unit) is configured to be pulled out from the apparatus. Therefore, a positional accuracy may decrease due to a fluctuation in components. Furthermore, to pull out the processing tray from the apparatus, it is necessary to ensure a sufficient space between the apparatus and an adjacent member. As a result, a positional relation between the processing tray and the staple discharge roller becomes unstable. Consequently, an angle of a sheet entering to the processing tray fluctuates as indicated by dashed arrows shown in FIG. 42, and thus it may cause a jam or damage to the sheet.
Furthermore, such a configuration of the sheet processing device has difficulty fixing a sheet jam occurring at a joint portion between the main body of the sheet processing device and the processing tray. If the processing tray is pulled out from the apparatus in a state where a sheet jam occurs at the joint portion, a sheet is damaged because both sides of the sheet are held between sheet conveying rollers. To avoid such a situation, a user has to shift the sheet manually to either the side of the main body of the sheet processing device or the side of the processing tray. However, if no conveying member is provided to the processing tray, it is not possible to shift the sheet.